Method and apparatus for efficient battery use by a handheld multiple function device

ABSTRACT

A method for efficient battery use begins by monitoring at least one output of the handheld device for an overload condition. The processing continues by monitoring a system voltage produced by a DC-to-DC converter for a system low voltage condition. The process continues by monitoring voltage of the battery for a battery low voltage condition. The processing then continues by enabling one of a plurality of fail-safe algorithms based on when one or more of the overload condition, the system low voltage condition, and/or the battery low voltage condition are detected.

[0001] This patent is claiming priority under 35 USC § 119(e) toprovisionally filed patent application entitled MULTI-FUNCTION HANDHELDDEVICE, having a provisional serial No. of 60/429,941 and a provisionalfiling date of Nov. 29, 2002.

BACKGROUND OF THE INVENTION

[0002] 1. Technical Field of the Invention

[0003] This invention relates generally to portable electronic equipmentand more particularly to efficient powering of such devices.

[0004] 2. Description of Related Art

[0005] As is known, integrated circuits are used in a wide variety ofelectronic equipment, including portable, or handheld, devices. Suchhandheld devices include personal digital assistants (PDA), CD players,MP3 players, DVD players, AM/FM radio, a pager, cellular telephones,computer memory extension (commonly referred to as a thumb drive), etc.Each of these handheld devices include one or more integrated circuitsto provide the functionality of the device. For example, a thumb drivemay include an integrated circuit for interfacing with a computer (e g.,personal computer, laptop, server, workstation, etc.) via one of theports of the computer (e.g., Universal Serial Bus, parallel port, etc.)and at least one other memory integrated circuit (e.g., flash memory).As such, when the thumb drive is coupled to a computer, data can be readfrom and written to the memory of the thumb drive. Accordingly, a usermay store personalized information (e.g., presentations, Internet accessaccount information, etc.) on his/her thumb drive and use any computerto access the information.

[0006] As another example, an MP3 player may include multiple integratedcircuits to support the storage and playback of digitally formattedaudio (i.e., formatted in accordance with the MP3 specification). As isknown, one integrated circuit may be used for interfacing with acomputer, another integrated circuit for generating a power supplyvoltage, another for processing the storage and/or playback of thedigitally formatted audio data, and still another for rendering theplayback of the digitally formatted audio data audible.

[0007] Integrated circuits have enabled the creation of a plethora ofhandheld devices, however, to be “wired” in today electronic world, aperson needs to posses multiple handheld devices. For example, one mayown a cellular telephone for cellular telephone service, a PDA forscheduling, address book etc., one or more thumb drives for extendedmemory functionality, an MP3 player for storage and/or playback ofdigitally recorded music, a radio, etc. Thus, even though a singlehandheld device may be relatively small, carrying multiple handhelddevices on one's person can become quite burdensome.

[0008] A vital concern with every battery powered handheld device is itsbattery life (i.e., how long the handheld device will run before thebattery has to be replaced). There are two primary components toextending the battery life of a handheld device: one is to minimizepower consumption and the other is to use the battery to its fullestcapacity. Most of the efforts to date with respect to battery life havebeen focused on reducing power consumption. While this is extremelyimportant, using the battery to its fullest extent is becoming morecritical and getting some attention.

[0009] Current techniques to use the battery to its fullest extentsafely (i.e., shutting down the handheld device in a safe manner whenthe battery is consumed) monitor the battery voltage. When the batteryvoltage drops below a threshold, the handheld device is shutdown bystoring current user settings et cetera such that when the battery isreplaced, the handheld device comes up in a known manner and, ifdesired, where it left off just before the battery was replaced. If thehandheld device is not shutdown in a known manner when the batteryvoltage drops below the threshold, the software of the handheld devicemay lock-up causing the handheld device to require service.

[0010] While monitoring the battery voltage does provide a safe shutdownmechanism extending the usefulness of a battery, it does not enable thebattery to be used to its fullest extent, nor does it distinguish thepossible reasons as to why the battery voltage dropped.

[0011] Therefore, a need exists for a method and apparatus thatmaximizes battery life based on operating conditions of a batterypowered handheld device.

BRIEF SUMMARY OF THE INVENTION

[0012] The method and apparatus for efficient battery use by a handheldmultifunction device of the present invention substantially meets theseneeds and others. In one embodiment, a method for efficient battery usebegins by monitoring at least one output of the handheld device for anoverload condition. For example, the headphone jack output may bemonitored for an overload condition, which may be caused by an improperinstallation of a headphone, a short, et cetera. The processingcontinues by monitoring a system voltage produced by a DC-to-DCconverter for a system low voltage condition. For example, based on thepower requirements to be sourced by the DC-to-DC converter, the DC-to-DCconverter is overloaded such that its output voltage is drooping. Theprocess continues by monitoring voltage of the battery for a battery lowvoltage condition. For example, the battery voltage may be monitored forfalling below a threshold, which may result from extended use or failingto make adequate electrical contact with the terminals of the handhelddevice. The processing then continues by enabling one of a plurality offail safe algorithms based on when one or more of the overloadcondition, the system low voltage condition, and/or the battery lowvoltage condition are detected. With such a method, and/or apparatusincorporating such a method, the battery life of a handheld device maybe taken to its fullest extent and just before the battery hasinsufficient power to power the handheld device, the handheld device ispartially or fully shutdown in a safe manner.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0013]FIG. 1 is a schematic block diagram of a multifunction handhelddevice in accordance with the present invention;

[0014]FIG. 2 is a schematic block diagram of another multifunctionhandheld device in accordance with the present invention;

[0015]FIG. 3 is a schematic block diagram of an integrated circuit foruse in a multifunction handheld device in accordance with the presentinvention;

[0016]FIG. 4 is a schematic block diagram of another integrated circuitfor use in a multifunction handheld device in accordance with thepresent invention;

[0017]FIG. 5 is a schematic block diagram of the handheld deviceproviding efficient battery use in accordance with the presentinvention;

[0018]FIG. 6 is a graph plotting battery consumption versus batteryvoltage;

[0019]FIG. 7 is a graph plotting supply voltage versus power consumptionfor CMOS integrated circuits;

[0020]FIG. 8 is a logic diagram of a method for efficient battery use bya handheld device in accordance with the present invention and

[0021] FIGS. 9-12 are logic diagrams regarding the plurality offail-safe algorithms that may be performed in accordance with the methodof FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

[0022]FIG. 1 is a schematic block diagram of a multi-function handhelddevice 10 and corresponding integrated circuit 12 operably coupled to ahost device A, B, or C. The multi-function handheld device 10 alsoincludes memory integrated circuit (IC) 16 and a battery 14. Theintegrated circuit 12 includes a host interface 18, a processing module20, a memory interface 22, a multimedia module 24, a DC-to-DC converter26, and a bus 28. The multimedia module 24 alone or in combination withthe processing module 20 provides the functional circuitry for theintegrated circuit 12. The DC-to-DC converter 26, which may beconstructed in accordance with the teaching of U.S. Pat. No. 6,204,651,entitled METHOD AND APPARATUS FOR REGULATING A DC VOLTAGE, provides atleast a first supply voltage to one or more of the host interface 18,the processing module 20, the multimedia module 24, and the memoryinterface 22. The DC-to-DC converter 26 may also provide V_(DD) to oneor more of the other components of the handheld device 10.

[0023] When the multi-function handheld device 10 is operably coupled toa host device A, B, or C, which may be a personal computer, workstation,server (which are represented by host device A), a laptop computer (hostdevice B), a personal digital assistant (host device C), and/or anyother device that may transceiver data with the multi-function handhelddevice, the processing module 20 performs at least one algorithm 30,where the corresponding operational instructions of the algorithm 30 arestored in memory 16 and/or in memory incorporated in the processingmodule 20. The processing module 20 may be a single processing device ora plurality of processing devices. Such a processing device may be amicroprocessor, micro-controller, digital signal processor,microcomputer, central processing unit, field programmable gate array,programmable logic device, state machine, logic circuitry analogcircuitry, digital circuitry, and/or any device that manipulates signals(analog and/or digital) based on operational instructions. Theassociated memory may be a single memory device or a plurality of memorydevices. Such a memory device may be a read-only memory, random accessmemory, volatile memory, non-volatile memory, static memory, dynamicmemory, flash memory, and/or any device that stores digital information.Note that when the processing module 20 implements one or more of itsfunctions via a state machine, analog circuitry, digital circuitry,and/or logic circuitry, the associated memory storing the correspondingoperational instructions is embedded with the circuitry comprising thestate machine, analog circuitry, digital circuitry, and/or logiccircuitry.

[0024] With the multi-function handheld device 10 in the firstfunctional mode, the integrated circuit 12 facilitates the transfer ofdata between the host device A, B, or C and memory 16, which may benon-volatile memory (e.g., flash memory, disk memory, SDRAM) and/orvolatile memory (e.g. DRAM). In one embodiment, the memory IC 16 is aNAND flash memory that stores both data and the operational instructionsof at least some of the algorithms 30.

[0025] In this mode, the processing module 30 retrieves a first set ofoperational instructions (e.g., a file system algorithm, which is knownin the art) from the memory 16 to coordinate the transfer of data. Forexample, data received from the host device A, B, or C (e.g., Rx data)is first received via the host interface module 18. Depending on thetype of coupling between the host device and the handheld device 10, thereceived data will be formatted in a particular manner. For example, ifthe handheld device 10 is coupled to the host device via a USB cable,the received data will be in accordance with the format proscribed bythe USB specification. The host interface module 18 converts the formatof the received data (e.g., USB format) into a desired format byremoving overhead data that corresponds to the format of the receiveddata and storing the remaining data as data words. The size of the datawords generally corresponds directly to, or a multiple of, the bus widthof bus 28 and the word line size (i.e., the size of data stored in aline of memory) of memory 16. Under the control of the processing module20, the data words are provided, via the memory interface 22, to memory16 for storage. In this mode, the handheld device 10 is functioning asextended memory of the host device (e.g., like a thumb drive).

[0026] In furtherance of the first functional mode, the host device mayretrieve data (e.g., Tx data) from memory 16 as if the memory were partof the computer. Accordingly, the host device provides a read command tothe handheld device, which is received via the host interface 18. Thehost interface 18 converts the read request into a generic format andprovides the request to the processing module 20. The processing module20 interprets the read request and coordinates the retrieval of therequested data from memory 16 via the memory interface 22. The retrieveddata (e.g., Tx data) is provided to the host interface 18, whichconverts the format of the retrieved data from the generic format of thehandheld device into the format of the coupling between the handhelddevice and the host device. The host interface 18 then provides theformatted data to the host device via the coupling.

[0027] The coupling between the host device and the handheld device maybe a wireless connection or a wired connection. For instance, a wirelessconnection may be in accordance with Bluetooth, IEEE 802.11(a), (b) or(g), and/or any other wireless LAN (local area network) protocol, IrDA,etc. The wired connection may be in accordance with one or more Ethernetprotocols, Firewire, USB, etc. Depending on the particular type ofconnection, the host interface module 18 includes a correspondingencoder and decoder. For example, when the handheld device 10 is coupledto the host device via a USB cable, the host interface module 18includes a USB encoder and a USB decoder.

[0028] As one of average skill in the art will appreciate, the datastored in memory 16, which may have 64 Mbytes or greater of storagecapacity, may be text files, presentation files, user profileinformation for access to varies computer services (e.g., Internetaccess, email, etc.), digital audio files (e.g., MP3 files, WMA-WindowsMedia Architecture-, MP3 PRO, Ogg Vorbis, AAC—Advanced Audio Coding),digital video files [e.g., still images or motion video such as MPEG(motion picture expert group) files, JPEG (joint photographic expertgroup) files, etc.] address book information, and/or any other type ofinformation that may be stored in a digital format. As one of averageskill in the art will further appreciate, when the handheld device 10 iscoupled to the host device A, B, or C, the host device may power thehandheld device 10 such that the battery is unused.

[0029] When the handheld device 10 is not coupled to the host device,the processing module 20 executes an algorithm 30 to detect thedisconnection and to place the handheld device in a second operationalmode. In the second operational mode, the processing module 20retrieves, and subsequently executes, a second set of operationalinstructions from memory 16 to support the second operational mode. Forexample, the second operational mode may correspond to MP3 fileplayback, digital dictaphone recording, MPEG file playback, JPEG fileplayback, text messaging display, cellular telephone functionality,and/or AM/FM radio reception. Each of these functions is known in theart, thus no further discussion of the particular implementation ofthese functions will be provided except to further illustrate theconcepts of the present invention.

[0030] In the second operational mode, under the control of theprocessing module 20 executing the second set of operationalinstructions, the multimedia module 24 retrieves multimedia data 34 frommemory 16. The multimedia data 34 includes at least one of digitizedaudio data, digital video data, and text data. Upon retrieval of themultimedia data, the multimedia module 24 converts the data 34 intorendered output data 36. For example, the multimedia module 24 mayconvert digitized data into analog signals that are subsequentlyrendered audible via a speaker or via a headphone jack. In addition, orin the alternative, the multimedia module 24 may render digital videodata and/or digital text data into RGB (red-green-blue), YUV etc., datafor display on an LCD (liquid crystal display) monitor, projection CRT,and/or on a plasma type display. The multimedia module 24 will bedescribed in greater detail with reference to FIGS. 2 and 3.

[0031] As one of average skill in the art, the handheld device 10 may bepackaged similarly to a thumb drive, a cellular telephone pager (e.g.,text messaging), a PDA, an MP3 player, a radio, and/or a digitaldictaphone and offer the corresponding functions of multiple ones of thehandheld devices (e.g., provide a combination of a thumb drive and MP3player/recorder, a combination of a thumb drive, MP3 player/recorder,and a radio, a combination of a thumb drive, MP3 player/recorder, and adigital dictaphone, combination of a thumb drive MP3 player/recorder,radio, digital dictaphone, and cellular telephone, etc.).

[0032]FIG. 2 is a schematic block diagram of another handheld device 40and a corresponding integrated circuit 12-1. In this embodiment, thehandheld device 40 includes the integrated circuit 12-1, the battery 14,the memory 16, a crystal clock source 42, one or more multimedia inputdevices (e.g., one or more video capture device(s) 44, keypad(s) 54,microphone(s) 46, etc.), and one or more multimedia output devices(e.g., one or more video and/or text display(s) 48 speaker(s) 50,headphone jack(s) 52, etc.). The integrated circuit 12-1 includes theyhost interface 18, the processing module 20, the memory interface 22,the multimedia module 24, the DC-to-DC converter 26, and a clockgenerator 56, which produces a clock signal (CLK) for use by the othermodules. As one of average skill in the art will appreciate, the clocksignal CLK may include multiple synchronized clock signals at varyingrates for the various operations of the multi-function handheld device.

[0033] Handheld device 40 functions in a similar manner as handhelddevice 10 when exchanging data with the host device (i.e., when thehandheld device is in the first operational mode). In addition, while inthe first operational mode, the handheld device 40 may store digitalinformation received via one of the multimedia input devices 44, 46, and54. For example, a voice recording received via the microphone 46 may beprovided as multimedia input data 58, digitized via the multimediamodule 24 and digitally stored in memory 16. Similarly, video recordingsmay be captured via the video capture device 44 (e.g., a digital camera,a camcorder, VCR output, DVD output, etc.) and processed by themultimedia module 24 for storage as digital video data in memory 16.Further, the key pad 54 (which may be a keyboard, touch screeninterface, or other mechanism for inputting text information) providestext data to the multimedia module 24 for storage as digital text datain memory 16. In this extension of the first operational mode, theprocessing module 20 arbitrates write access to the memory 16 among thevarious input sources (e.g., the host and the multimedia module).

[0034] When the handheld device 40 is in the second operational mode(i.e., not connected to the host), the handheld device may record and/orplayback multimedia data stored in the memory 16. Note that the dataprovided by the host when the handheld device 40 was in the firstoperational mode includes the multimedia data. The playback of themultimedia data is similar to the playback described with reference tothe handheld device 10 of FIG. 1. In this embodiment, depending on thetype of multimedia data 34, the rendered output data 36 may be providedto one or more of the multimedia output devices. For example, renderedaudio data may be provided to the headphone jack 52 and/or to thespeaker 50, while rendered video and/or text data may be provided to thedisplay 48.

[0035] The handheld device 40 may also record multimedia data 34 whilein the second operational mode. For example, the handheld device 40 maystore digital information received via one of the multimedia inputdevices 44, 46, and 54.

[0036]FIG. 3 is a schematic block diagram of an integrated circuit 12-2that may be used in a multi-function handheld device. The integratedcircuit 12-2 includes the host interface 18, the processing module 20,the DC-to-DC converter 26, memory 60, the clock generator 56, the memoryinterface 22, the bus 28 and the multimedia module 24. The DC-to-DCconverter 26 includes a first output section 62, and a second outputsection 64 to produce a first and second output voltage (V_(DD1) andV_(DD2)), respectively. Typically, V_(DD1) will be greater that V_(DD2),where V_(DD1) is used to source analog sections of the processing module20, the host interlace 18, the memory interface 22, and/or themultimedia module 22 and V_(DD2) is used to source the digital sectionsof these modules. The DC-to-DC converter 26 may further include abattery charger 63 and a low loss multiple output stage 62. The batterycharger 63 is operable to charge the battery 14 from power it receivesvia the physical coupling (e.g., via a USB cable) to the host devicewhen the multi-function handheld device is physically coupled to thehost device. The particular implementation of the battery charger 63 isdependent on the type of battery being used and such implementations areknown in the art, thus no further discussion will be provided regardingthe battery charger 63 except to further illustrate the concepts of thepresent invention.

[0037] The multimedia module 24 includes an analog input port 66, ananalog to digital converter (ADC) 68, an analog output port 70, adigital to analog converter (DAC) 72, a digital input port 74, a digitaloutput port 76; and an analog mixing module 78. The analog input port 66is operably coupled to receive analog input signals from one or moresources including a microphone, all AM/FM tuner, a line in connection(e.g., headphone jack of a CD player), etc. The received analog signalsare provided to the ADC 68, which produces digital input data therefrom.The digital input data may be in a pulse code modulated (PCM) format andstored as such, or it may be provided to the processing module 20 forfurther audio processing (e.g, compression, MP3 formatting, etc.) Thedigital input data, or the processed version thereof, is stored inmemory 16 as instructed by the processing module 20.

[0038] The digital input port 74 is operably coupled to receive digitalaudio and/or video input signals from, for example, a digit a camcorder,etc. The digital audio and/or video input signals may be stored inmemory 16 under the control of the processing module 20. As one ofaverage skill in the art will appreciate, the audio and/or video data(which was inputted as analog signals or digital signals) may be storedas raw data (i.e., the signals received are stored as is in designatedmemory locations) or it may be stored as processed data (i.e.,compressed data, MPEG data, MP3 data, WMA data, etc.).

[0039] The DAC 72 receives multimedia data 34 as digital output data andconverts it into analog video and/or audio output data that is providedto the mixing module 78. When the output of the DAC 72 is the only inputto the mixing module 78, the mixing module 78 outputs the analog videoand/or audio output data to the analog output port 70. The analog outputport 70 may be coupled to one or more of the speaker, headphone jack,and a video display. The mixing module 78 may mix analog input signalsreceived via the analog input port 66 with the output of DAC 72 toproduce a mixed analog signal that is provided to the analog output port70. Note that the buffers in series with the inputs of the mixing module78 may have their gains adjusted and/or muted to enable selection of thesignals at various gain settings provided to the mixing module 78 andsubsequently outputted via the analog output port 70.

[0040] The digital output port 76 is, operably coupled to output thedigital output data (i.e., the multimedia data 34 in a digital format).The digital output port 76 may be coupled to a digital input of a videodisplay device, another handheld device for direct file transfer, etc.

[0041] As one of average skill in the art will appreciate, themultimedia module 24 may include more or less components than thecomponents shown in FIG. 3 or include multiple analog and/or digitalinput and/or output ports. For example, for a playback mode of digitalaudio files, the multimedia module 24 may only include the DAC 72 andthe analog output port 70 that is coupled to the headphone jack and/orto the speaker. As another example, for recording voice samples (i.e.,as a digital dictaphone), the multimedia module 24 may include theanalog input port 66 coupled to the microphone and the ADC.

[0042]FIG. 4 is a schematic block diagram of an integrated circuit 12-3that may be incorporated in a multi-function handheld device 10 or 40.The integrated circuit 12-3 includes a general purpose input/outputmodule 80, a CD control interface 82, an I²C interface module 84, adisplay interface module 86, a static and/or dynamic RAM interface 88,an input interface module 90, processing module 20, ROM 35, RAM 33, aperipheral bus 104, a memory bus 106, a system-on-a-chip (SOC)management module 100, a universal serial bus (USB) interface 102, adigital-to-analog converter 72, an analog-to-digital converter 68, amultiplexer buffers, mixing module 78, DC to DC converter 26, aprogrammable driver 92, and a microphone bias module 96.

[0043] In operation, the integrated circuit 12-3 may facilitate thetransceiving of data with a host device between system memory of amulti-function handheld device and a host device, may playbackmultimedia data, and/or may record multimedia data via input ports. Whenthe integrated circuit 12-3 is transceiving with a host device, the USBinterface 102 operably couples the integrated circuit 12-3 to a hostdevice. In addition, the SDRAM interface 88 couples, either, via thegeneral purpose input/output module 80 or directly, to the system memory(e.g., memory IC 16) of the multi-function handheld device 10. In thisconfiguration, data that is received from the host device is placed onthe memory bus 106 by the USB interface 102. The SDRAM interface 88retrieves the data from the memory bus 106 and forwards it or storage tothe system memory under the control of the processing module 20 that isexecuting a file system storage algorithm. The data being stored maycorrespond to playback data, such as an MP3 file, a WMA file, a videofile, a text file, and/or a combination thereof. Alternatively, or inaddition to, the data being received from the host may correspond toprogramming instructions of an algorithm 30, which may be an MP3 decoderalgorithm, a WMA decoder algorithm, a MPEG algorithm, a JPEG algorithm,et cetera.

[0044] For providing data from the handheld device 10 to the hostdevice, the SDRAM interface 88 retrieves data from the system memory andplaces it on the memory bus 106 under the control of the processingmodule 20 as it executes a file system algorithm. The USB interface 102retrieves the data from the memory bus 106 and forwards it to the hostdevice in accordance with one of the versions of the USB standard.

[0045] Data may also be stored in the system memory that is received viathe CD (compact disk) control interface 82, and/or the I²C interface 84or other type of two or three wire data interface. Via these interfaces82 and 84, data is received via the general purpose input/output module80 and placed on the memory bus 106. The SDRAM interface 88 retrievesthe data from the memory bus 106 and provides it to the system memory,which is done under the control of the processing module as it executesa data storage algorithm.

[0046] When the integrated circuit 12-3 is recording audio inputsreceived via the microphone input, the microphone bias circuit 96provides the received audio signals to the mixing module 78 as well asto the multiplexer (mux) via a buffer. The microphone bias circuit 96biases the audio input for optimal operations. The received audio inputsignals are is converted to digital audio signals via theanalog-to-digital converter 68. The digital audio signals may then bestored in system memory (e.g., memory IC 16). Alternatively, the audioinput signal may be provided to the summing module 78 and subsequentlyprovided to headphone jack 94 via the programmable driver 92 as acomponent of a summed analog signal. The summing module 78 may sum, orpass any one of, the audio input signals may be mixed with other analoginput signals, such as a line input, an FM radio input, and the analogoutput of the DAC 72, to produce the summed signal.

[0047] When the integrated circuit 12-3 is in a playback mode, digitalmultimedia data is retrieved from the system memory and provided to thedigital-to-analog converter 72. The digital-to-analog converter 72converts the digital multimedia signals, which may be audio data, videodata and/or text data, into analog multimedia signals and provides theanalog multimedia signals to mixing module 78. In the playback mode, themixing module 78 will generally have the other inputs muted, such thatits output corresponds directly to the analog multimedia signalsprovided by the digital-to-analog converter 72.

[0048] The programmable driver 92 increases the drive power of theanalog multimedia signals (e.g., audio signals when the analogmultimedia signals are provided to a headphone) and provides it to theheadphone jack 94. As one of average skill in the art will appreciate, afixed driver may replace the programmable driver 92 to drive theheadphone jack 94.

[0049] To place the integrated circuit 12-3 into the various operationalmodes, commands are received via the general purpose input/output module80 by the input interface 90. The input interface 90 receives the inputstimulus corresponding to commands, interprets the input stimulus togenerate the corresponding commands. The commands are then provided onthe peripheral bus 104 and/or the memory bus 106 and processed by theprocessing module 20.

[0050] In addition to producing audio outputs during playback mode, theintegrated circuit 12-3 may provide video outputs via, the displayinterface 86, which will be described in greater detail with referenceto FIG. 14. The display interface 86 drives the display, which may be anLCD display, LED display, plasma display and/or any other type ofdisplay. The data being displayed may correspond to the multimedia dataretrieved from the system memory, and/or may correspond to the commandsinputted via the input interface 90.

[0051] The system-on-a-chip (SOC) management module 100 processesinterrupt controls, generates clock signals for the integrated circuit12-3, performs bit manipulations, performs debugging operations, andexecutes a Reed-Solomon, or other type of encoding/decoding algorithm toencode and/or decode data.

[0052] The DC-to-DC converter 26, provides at least one supply voltagefor the integrated circuit 12-3 and typically provides two supplyvoltages. For example, the DC-to-DC converter 26 may produce a 3.3 voltssupply and a 1.8 volt supply.

[0053]FIG. 5 is a schematic block diagram of the handheld device ofFIGS. 1 and/or 2 consuming power and managing the power consumption toprovide efficient battery use in accordance with the present invention.As shown, battery 14 produces a battery voltage that, via a switch, iscoupled to the DC-to-DC converter 26. The DC-to-DC converter produces asystem voltage 112 which may correspond to V_(DD 1) or V_(DD 2) as shownin FIGS. 1-4. The multimedia module 24 is powered via the system voltage112 and produces at least one output as shown in FIGS. 2 and 3. In thisillustration, only the headphone jack 52 output of the multimedia moduleis shown. As shown, a pair of headphones 110 may be coupled to theheadphone jack 52.

[0054] In operation, the processing module 20 executes an algorithm, aswell be further described with reference to FIGS. 8-12, to monitor thebattery usage by the handheld device and to ensure that, once thebattery has been as close to fully consumed as possible, the handhelddevice is fully shutdown or at least partially shutdown in a safe mannersuch that when the battery is replaced the handheld device will come upcorrectly. To facilitate the efficient battery use algorithm, theprocessing module 20 monitors the battery voltage, the system voltage112 and/or the current and/or voltage of each output of the multimediamodule 24, in this example the headphone jack 52. Typically, themonitoring of an output of the multimedia module 24 will be detectingwhether an overload condition, produced by a short circuit, and/orfaulty equipment coupled thereto, results in an excessive amount ofpower being drawn by that particular output. For example, if theheadphones were faulty such that they cause a short within the headphonejack 52, an overload condition would result. When an overload conditionresults, the processing module 20 disables the output for apredetermined period of time (e.g., one second to ten seconds). When thepredetermined period of time expires, the processing module 20 enablesthe output again and resumes monitoring for an overload condition. Ifthe overload condition persists, the output is again disabled. Thedisabling and enabling of the output may be done by a switch mechanismand/or by placing an output driver at a high impedance state to disable,for this example, the headphone jack 52. If the overload conditionpersists after several retries, the processing module 20 may cease tocontinue the retry and generate an error message for display on thehandheld device indicating that the particular output is experiencing anoverload condition.

[0055] The processing module 20 also monitors the system voltage 112 fora system low voltage condition. A system low voltage condition resultswhen, for example, the desired system voltage 112 is 3.3 volts and dropsfrom the 3.3 voltage by a few percentile or more. The tolerance for thelow system voltage condition may be relatively small (e.g., a fewpercent voltage drop) based on how well the output(s) of the DC-to-DCconverter 26 are regulated. The less well regulated the output supply ofthe DC-to-DC converter is, the greater the tolerance needs to be for thelow, system voltage condition. The drop in the system voltage 112 mayinclude or exclude load transients that cause ripple on the output ofthe DC-to-DC converter 26.

[0056] When a low system voltage condition arises, it is indicative thatthe amount of power being consumed by the handheld device is beyond theremaining power capacity of the battery 14 but is not causingdangerously low output voltages to be generated, which might result inan unsafe shutdown of the handheld device. In this instance, theprocessing module may disable one or more of the outputs of the handhelddevice, store the current settings of operation of the handheld device(e.g., volume setting, which particular song is being played from an MP3storage file, bass settings, treble settings, et cetera). Once thesesettings have been stored, the handheld device is shutdown such thatwhen the battery is replaced and the handheld device is reactivated, theoperation continues where it left off. Alternatively, the processingmodule may shutdown only a portion of the handheld device. For examplethe processing module for the low system voltage condition may shutdownthe headphone jack which is a primary consumer of power for the handhelddevice but still allow for data file transfers and/or other low powerconsuming activities.

[0057] The processing module 20 also monitors the battery voltage.Typically, if the battery voltage drops below a particular threshold, inlight of the monitoring of the system voltage 112 and the overloadcondition of one or more outputs, it is indicative that the battery isnot making adequate contact with the power terminals of the handhelddevice thus appearing as no battery is present. When this condition isdetected, the processing module stores essential settings correspondingto the execution of a functional algorithm being performed and shutsdown the device. In this manner, the algorithm is terminated in apredictable manner, as opposed to crashing the algorithm, thus, when thedevice is restarted, the algorithm can be predictably be restarted.

[0058]FIGS. 6 and 7 illustrate graphs regarding power consumption of abattery. As shown in FIG. 6, battery consumption is plotted versusbattery voltage. As the battery consumption approaches 100%, the batteryvoltage drops. The goal of the processing module 20 of FIG. 5 is to takethe battery consumption as close to 100% as possible without damagingthe software stored within the handheld device, which may occur if thehandheld device loses power and does not shutdown in a safe manner. Assuch, by monitoring multiple points within the handheld device, thedevice may be shutdown in a safe manner while taking the batteryconsumption as close to 100% as possible.

[0059]FIG. 7 is a graph that plots versus power consumption for CMOSintegrated circuits. As shown, as the supply voltage increases the powerconsumption of an IC increases nonlinearly, which increases consumptionof the battery (i.e., reduces battery life). Thus, the processing modulemonitors the battery voltage as the battery consumption is increasedand, based on the power consumption of an IC versus supply voltagecurve, determines how much power of the, battery is left to power thehandheld device. Based on the known amount of power available in thebattery versus how much power is consumed by each of the portions of thehandheld device, including the outputs, the processing module maydetermine whether the entire handheld device needs to be shutdown oronly a portion thereof when a low system voltage condition is detected.

[0060]FIG. 8 is a logic diagram of a method for efficient battery use bya handheld device. As shown, the process begins at Step 120, 122 and124. As one of average skill in the art will appreciate, the efficientbattery by a handheld device may include one or more of the processingSteps 120, 122 and 124 and their associated steps.

[0061] At Step 120, at least one output of the handheld device ismonitored for an overload condition. The process then proceeds to Step126 where a determination is made as to whether an overload conditionoccurs. If not, the process loops back to the beginning of Step 120.Note that an overload condition may be detected by determining theoutput current provided to the particular output and when the outputcurrent exceeds a threshold indicating the overload condition.

[0062] If, however, an overload condition occurs, the process proceedsto Step 128 where a fail-safe algorithm regarding the overload conditionis enabled. Such a fail-safe algorithm may be implemented as shown inFIG. 9.

[0063] At Step 138 of FIG. 9, the overload condition fail-safe algorithmbegins by disabling the at least one output for a predetermined periodof time (e.g., at least one second). The process then proceeds to Step140 where after the expiration of the predetermined period of time, theat least one output is enabled. The process then proceeds to Step 142where the at least one output is monitored again for an overloadcondition. If an overload condition persists the processing module maygenerate an error message indicating the overload condition.

[0064] Returning to the logic diagram of FIG. 8, at Step 122 aprocessing module monitors a system voltage produced by the DC-to-DCconverter for a system low voltage condition. The process then proceedsto Step 130 where determination is made as to whether the low systemvoltage condition exists. If not, the process reverts to Step 122. Notethat the system low voltage condition may be determined by determiningloading on one or more outputs of the DC-to-DC converter, determiningthe available power, duration based on the loading and on the batteryvoltage, and, when the available power duration is less than the poweravailable threshold, indicating the low system voltage condition. Thiswas illustrated and discussed with reference to FIGS. 6 and 7.

[0065] If a low system voltage condition exists, the process proceeds toStep 132. At Step 132 the processing module enables a fail-safealgorithm regarding the low system voltage condition. The fail-safealgorithm for the low system voltage condition may be implemented asshown in FIG. 10 and/or FIG. 11.

[0066] In FIG. 10, the fail-safe algorithm begins at Step 144 where atleast one output of the handheld device is disabled. The process thenproceeds to Step 146 where the current settings correspond to executionof at least one functional algorithm is stored. The functional algorithmmay be playing of an MP3 file, recording an MP3 file, data transfer etcetera. Thus, the particular settings of the current execution of thisalgorithm are stored such that the algorithm may be shutdown in a safemanner without corruption. The process then proceeds to Step 148 wherethe handheld device is shutdown.

[0067]FIG. 11 illustrates an alternate fail-safe algorithm for the lowsystem voltage condition. The processing begins at Step 150 where aportion of the handheld device is disabled. The process then proceeds toStep 152 where current settings corresponding to the execution of atleast one functional algorithm related to the particular portion thathas been disabled, are stored. The process then proceeds to Step 154where the operation of the handheld device continues in a limited, lowpower consumption mode.

[0068] Returning to the logic diagram of FIG. 8, at Step 124, theprocessing module monitors the voltage of the battery for a battery lowvoltage condition. The process then proceeds to Step 134 where adetermination is made as to whether a low battery voltage conditionexists. If not, the process loops back to Step 124. If, however, a lowbattery voltage condition exists, the process proceeds to Step 136 wherea fail-safe algorithm regarding the low battery voltage is enabled.

[0069]FIG. 12 illustrates an example of ad fail-safe algorithm for a lowbattery voltage condition. The process begins at Step 156 whereessential current settings correspond to execution of at least onealgorithm are stored. The process then proceeds to Step 158 where thehandheld device is shutdown.

[0070] As one of average skill in the art will appreciate, the term“substantially” or “approximately”, as may be used herein, provides anindustry-accepted tolerance to its corresponding term. Such anindustry-accepted tolerance ranges from less than one percent to twentypercent and corresponds to, but is not limited to, component values,integrated circuit process variations, temperature variations, rise andfall times, and/or thermal noise. As one of average skill in the artwill further appreciate, the term “operably coupled”, as may be usedherein, includes direct coupling and indirect coupling via anothercomponent, element, circuit or module where, for indirect coupling, theintervening component, element, circuit, or module does not modify theinformation of a signal but may adjust its current level, voltage level,and/or power level. As one of average skill in the art will alsoappreciate, inferred coupling (i.e., where one element is coupled toanother element by inference) includes direct and indirect couplingbetween two elements in the same manner as “operably coupled”. As one ofaverage skill in the art will further appreciate, the term comparesfavorably”, as may be used herein, indicates that a comparison betweentwo or more elements, items, signals, etc., provides a desiredrelationship. For example, when the desired relationship is that signal1 has a greater magnitude than signal 2, a favorable comparison may beachieved when the magnitude of signal 1 is greater than that of signal 2or when the magnitude of signal 2 is less than that of signal 1.

[0071] The preceding discussion has presented a method and apparatus forefficient battery use by a handheld device. By monitoring multiplepoints within the handheld device, the battery life may be extended byutilizing the battery as close to 100% of its capabilities as possible.As one of average skill in the art will appreciate, other embodimentsmay be derived from the teaching of the present invention withoutdeviating from the scope of the claims.

What is claimed is:
 1. A method for efficient battery use by a handheldmultiple function device, the method comprises: monitoring at least oneoutput for an overload condition; monitoring a system voltage producedby a DC-to-DC converter for a system low voltage condition; monitoringvoltage of the battery for a battery low voltage condition; and enablingone of a plurality of fail safe algorithms based on when one or more ofthe overload condition, the system low voltage, condition, and thebattery low voltage condition are detected.
 2. The method of claim 1,wherein the enabling one of the plurality of fail safe algorithmsfurther comprises: when the overload condition is detected and when thesystem low voltage condition and the battery low voltage condition arenot detected, enabling a first fail safe algorithm of the plurality offailsafe algorithms to: disable the at least one output for apredetermined period of time; after expiration of the predeterminedperiod of time, enable the at least one output; and resume monitoring ofthe at least one output for the overload condition.
 3. The method ofclaim 1, wherein the enabling one of the plurality of fail safealgorithms further comprises: when the system low voltage condition isdetected and when the overload condition is not detected, enabling asecond fail safe algorithm of the plurality of fail safe algorithms to:disable the at least one output; store current settings corresponding toexecution of at least one functional algorithm; and shutdown thehandheld multiple function device.
 4. The method of claim 1, wherein theenabling one of the plurality of fail safe algorithms further comprises:when the battery low voltage condition is detected, enabling a thirdfail safe algorithm of the plurality of fail safe algorithms to: storeessential current settings corresponding to execution of at least onefunctional algorithm; and shut down the handheld multiple functiondevice.
 5. The method of claim 1, wherein the monitoring the at leastone output for the overload condition further comprises: determiningoutput current provided to the at least one output; and when the outputcurrent exceeds a current threshold, identifying the overload condition.6. The method of claim 1, wherein the monitoring a system voltageproduced by the DC-to-DC converter for a system low voltage conditionfurther comprises: determining loading on an output of the DC-to-DCconverter that is providing the system voltage; determining availablepower duration based on the loading and the voltage of the battery; andwhen the available power duration is less than a power availablethreshold, indicating the system low voltage condition.
 7. The method ofclaim 1, wherein the enabling one of the plurality of fail safealgorithms further comprises: when the system low voltage condition isdetected and when the overload condition is not detected, enabling asecond fail safe algorithm of the plurality of fail safe algorithms to:disable a portion of the handheld multiple function device; storecurrent settings corresponding to execution of at least one functionalalgorithm processed by the portion of the handheld multiple functiondevice; and continuing operation of the handheld, multiple functiondevice in a limited, low power consumption mode.
 8. A method forefficient battery use by a handheld multiple function device, the methodcomprises: monitoring at least one output for an overload condition;monitoring: voltage of the battery for a battery low voltage condition,or system voltage produced by a DC-to-DC converter for a system lowvoltage condition; and enabling one of a plurality of fail safealgorithms based on when one or more of the overload condition, thesystem low voltage condition, and the battery low voltage condition aredetected.
 9. The method of claim 8, wherein the enabling one of theplurality of fail safe algorithms further comprises: when the overloadcondition is detected and when the system low voltage condition and thebattery low voltage condition are not detected, enabling a first failsafe algorithm of the plurality of fail safe algorithms to: disable theat least one output for a predetermined period of time; after expirationof the predetermined period of time, enable the at least one output; andresume monitoring of the at least one output for the overload condition.10. The method of claim 8, wherein the enabling one of the plurality offail safe algorithms further comprises: when the battery low voltagecondition is detected, enabling a third fail safe algorithm of theplurality of fail safe algorithms to: store essential current settingscorresponding to execution of at least one functional algorithm; andshutdown the handheld multiple function device.
 11. The method of claim8, wherein the monitoring the at least one output for the overloadcondition further comprises: determining output current provided to theat least one output; and when the output current exceeds a currentthreshold, identifying the overload condition.
 12. A method forefficient battery use by a handheld multiple function device, the methodcomprises: monitoring voltage of the battery for a battery low voltagecondition; monitoring a system voltage produced by a DC-to-DC converterfor a system low voltage condition; and enabling one of a plurality offail safe algorithms based on when one or more of the system low voltagecondition and the battery low voltage condition are detected.
 13. Themethod of claim 12, wherein the enabling one of the plurality of failsafe algorithms further comprises: when the system low voltage conditionis detected and when the overload condition is not detected, enabling asecond fail safe algorithm of the plurality of fail safe algorithms to:disable the at least one output, store current settings corresponding toexecution of at least one functional algorithm; and shutdown thehandheld multiple function device.
 14. The method of claim 12, whereinthe monitoring a system voltage produced by the DC-to-DC converter for asystem low voltage condition further comprises: determining loading onan output of the DC-to-DC converter that is providing the systemvoltage; determining available power duration based on the loading andthe voltage of the battery; and when the available power duration isless than a power available threshold, indicating the system low voltagecondition.
 15. The method of claim 12, wherein the enabling one of theplurality of fail safe algorithms further comprises: when the system lowvoltage condition is detected and when the overload condition is notdetected, enabling a second fall safe algorithm of the plurality of failsafe algorithms to: disable a portion of the handheld multiple functiondevice; store current settings corresponding to execution of at leastone functional algorithm processed by the portion of the handheldmultiple function device; and continuing operation of the handheldmultiple function device in a limited, low power consumption mode. 16.An apparatus for efficient battery use by a handheld multiple functiondevice, the apparatus comprises: processing module; memory operablycoupled to the processing module, wherein the memory includesoperational instructions that cause the processing module to: monitor atleast one output for an overload condition; monitor a system voltageproduced by a DC-to-DC converter for a system low voltage condition;monitor voltage of the battery for a battery low voltage condition; andenable one of a plurality of fail safe algorithms based on when one ormore of the overload condition, the system low voltage condition, andthe battery low voltage condition are detected.
 17. The apparatus ofclaim 16, wherein the memory further comprises operational instructionsthat cause the processing module to enable one of the plurality of failsafe algorithms by: when the overload condition is detected and when thesystem low voltage condition and the battery low voltage condition arenot detected, enabling a first fail safe algorithm of the plurality offail safe algorithms to: disable the at least one output for apredetermined period of time; after expiration of the predeterminedperiod of time, enable the at least one output; and resume monitoring ofthe at least one output for the overload condition.
 18. The apparatus ofclaim 16, wherein the memory further comprises operational instructionsthat cause the processing module to enable one of the plurality of failsafe algorithms by: when the system low voltage condition is detectedand when the overload condition is not detected, enabling a second failsafe algorithm of the plurality of fail safe algorithms to: disable theat least one output; store current settings corresponding to executionof at least one functional algorithm; and shutdown the handheld multiplefunction device.
 19. The apparatus of claim 16, wherein the memoryfurther comprises operational instructions that cause the processingmodule to enable one of the plurality of fail safe algorithms by: whenthe battery low voltage condition is detected, enabling a third failsafe algorithm of the plurality of fail safe algorithms to: storeessential current settings corresponding to execution of at least onefunctional algorithm; and shutdown the handheld multiple functiondevice.
 20. The apparatus of claim 16, wherein the memory furthercomprises operational instructions that cause the processing module tomonitor the at least one output for the overload condition by:determining output current provided to the at least one output; and whenthe output current exceeds a current threshold, identifying the overloadcondition.
 21. The apparatus of claim 16, wherein the memory furthercomprises operational instructions that cause the processing module tomonitor a system voltage produced by the DC-to-DC converter for a systemlow voltage condition by: determining loading on an output of theDC-to-DC converter that is providing the system voltage; determiningavailable power duration based on the loading and the voltage of thebattery; and when the available power duration is less than a poweravailable threshold, indicating the system low voltage condition. 22.The apparatus of claim 16, wherein the memory further comprisesoperational instructions that cause the processing module to enable oneof the plurality of fail safe algorithms by: when the system low voltagecondition is detected and when the overload condition is not detected,enabling a second fail safe algorithm of the plurality of fail safealgorithms to: disable a portion of the handheld multiple functiondevice; store current settings corresponding to execution of at leastone functional algorithm processed by the position of the handheldmultiple function device; and continuing operation of the handheldmultiple function device in a limited, low power consumption mode. 23.An apparatus for efficient battery use by a handheld multiple functiondevice, the apparatus comprises: processing module; and memory operablycoupled to the processing module, wherein the memory stores operationalinstructions that cause the processing module to: monitor at least oneoutput for an overload condition; monitor at least one of: voltage ofthe battery for a battery low voltage condition, and system voltageproduced by a DC-to-DC converter for a system low voltage condition; andenable one of a plurality of fail safe algorithms based on when one ormore of the overload condition, the system low voltage condition, andthe battery low voltage condition are detected.
 24. The apparatus ofclaim 23, wherein the memory further comprises operational instructionsthat cause the processing module to enable one of the plurality of failsafe algorithms by: when the overload condition is detected and when thesystem low voltage condition and the battery low voltage condition arenot detected enabling a first fail safe algorithm of the plurality offail safe algorithms to: disable the at least one output for apredetermined period of time; after expiration of the predeterminedperiod of time, enable the at least one output; and resume monitoring ofthe at least one output for the overload condition.
 25. The apparatus ofclaim 23, wherein the memory further comprises operational instructionsthat cause the processing module to enable one of the plurality of failsafe algorithms by: when the battery low voltage condition is detected,enabling a third fail safe algorithm of the plurality of fail safealgorithms to: store essential current settings corresponding toexecution of at least one functional algorithm; and shut down thehandheld multiple function device.
 26. The apparatus of claim 23,wherein the memory further comprises operational instructions that causethe processing module to monitor the at least one output for theoverload condition further comprises: determining output currentprovided to the at least one output; and when the output current exceedsa current threshold, identifying the overload condition.
 27. Anapparatus for efficient battery use by a handheld multiple functiondevice, the apparatus comprises: processing module; and memory operablycoupled to the processing module, wherein the memory stores operationalinstructions that cause the processing module to: monitor voltage of thebattery for a battery low voltage condition; monitor a system voltageproduced by a DC-to-DC converter for a system low voltage condition; andenable one of a plurality of fail safe algorithms based on when one ormore of the system low voltage condition and the battery low voltagecondition are detected.
 28. The apparatus of claim 27, wherein thememory further comprises operational instructions that cause theprocessing module to enable one of the plurality of fail safe algorithmsby: when the system low voltage condition is detected and when theoverload condition is not detected, enabling a second fail safealgorithm of the plurality of fail safe algorithms to: disable the atleast one output; store current settings corresponding to execution ofat least one functional algorithm; and shutdown the handheld multiplefunction device.
 29. The apparatus of claim 27, wherein the memoryfurther comprises operational instructions that cause the processingmodule to monitor a system voltage produced by the DC-to-DC converterfor a system low voltage condition by: determining loading on an outputof the DC-to-DC converter that is providing the system voltage;determining available power duration based on the loading and thevoltage of the battery; and when the available power duration is lessthan a power available threshold, indicating the system low voltagecondition.
 30. The apparatus of claim 27, wherein the memory furthercomprises operational instructions that cause the processing module toenable one of the plurality of fail safe algorithms by: when the systemlow voltage condition is detected and when the overload condition is notdetected, enabling a second fail safe algorithm of the plurality of failsafe algorithms to: disable a portion of the handheld multiple functiondevice; store current settings corresponding to execution of at leastone functional algorithm processed by the portion of the handheldmultiple function device; and continuing operation of the handheldmultiple function device in a limited, low power consumption mode.